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    Subject[patch 07/28] Add cmpxchg_local to arm
    Use the new generic cmpxchg_local (disables interrupt). Also use the generic
    cmpxchg as fallback if SMP is not set.

    Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    CC: clameter@sgi.com
    CC: rmk@arm.linux.org.uk
    ---
    include/asm-arm/system.h | 41 ++++++++++-------------------------------
    1 file changed, 10 insertions(+), 31 deletions(-)

    Index: linux-2.6-lttng/include/asm-arm/system.h
    ===================================================================
    --- linux-2.6-lttng.orig/include/asm-arm/system.h 2007-08-27 11:16:14.000000000 -0400
    +++ linux-2.6-lttng/include/asm-arm/system.h 2007-08-27 11:31:59.000000000 -0400
    @@ -350,40 +350,19 @@ static inline unsigned long __xchg(unsig
    extern void disable_hlt(void);
    extern void enable_hlt(void);

    -#ifndef CONFIG_SMP
    +#include <asm-generic/cmpxchg-local.h>
    +
    /*
    - * Atomic compare and exchange.
    + * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
    + * them available.
    */
    -#define __HAVE_ARCH_CMPXCHG 1
    -
    -extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
    -
    -static inline unsigned long __cmpxchg(volatile void *ptr,
    - unsigned long old,
    - unsigned long new, int size)
    -{
    - unsigned long flags, prev;
    - volatile unsigned long *p = ptr;
    -
    - if (size == 4) {
    - local_irq_save(flags);
    - prev = *p;
    - if (prev == old)
    - *p = new;
    - local_irq_restore(flags);
    - return prev;
    - } else
    - return wrong_size_cmpxchg(ptr);
    -}
    -
    -#define cmpxchg(ptr, o, n) \
    -({ \
    - __typeof__(*(ptr)) _o_ = (o); \
    - __typeof__(*(ptr)) _n_ = (n); \
    - (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
    - (unsigned long)_n_, sizeof(*(ptr))); \
    -})
    +#define cmpxchg_local(ptr,o,n) \
    + (__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o), \
    + (unsigned long)(n), sizeof(*(ptr)))
    +#define cmpxchg64_local(ptr,o,n) __cmpxchg64_local_generic((ptr), (o), (n))

    +#ifndef CONFIG_SMP
    +#include <asm-generic/cmpxchg.h>
    #endif

    #endif /* __ASSEMBLY__ */
    --
    Mathieu Desnoyers
    Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
    -
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